Oil soluble orange and yellow dyes



3,M9,533 Patented Aug. 14, 1962 Free 3,049,533 OE. SOLUBLE ORANGE AND YELLOW DYES Penn F. Spitzer, Jr., Bound Brook, and Fridtjof Aagaard,

Rahway, N.J., assignors to American Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Filed Mar. 18, 1960, Ser. No. 15,795 2 Claims. (Cl. 260-197) This invention relates to improved oil soluble azo dyes, one a yellow dye (Old Color Index No. 19 or New Color Index No. llOQO) having the formula V on,

and the other an orange dye (Old Color Index No. 24 or New Color Index No. 12055) having the formula:

The principal use for these dyes is to color hydrocarbon fuels, such as gasoline stock and fuel oil, either for identification as to grade or origin or in some cases for sales appeal. Thus, for example, some gasolines having desirable anti-knock characteristics are not clear and color less, and the coloring of such fuels a uniform yellow or orange produces an article which is more attractive to the consumer.

The method of introducing the small amount of the particular coloring matter used in gasolines or other fuels must be relatively simple and inexpensive for the fuel itself is relatively low in price and ordinarily the margin of profit will not stand extensive labor costs.

One of the least expensive and most satisfactory methods is by the so-called dry dye eduction method in which a small amount of finely divided dye is drawn into an eductor probe by vacuum where it is co-mixed with a stream of gasoline or fuel oil and carried to a storage tank. The

dry dye eduction method, however, imposes some drastic limitations on the physical characteristics of the color entirely apart from its solubility in hydrocarbons. Thus, the colors must be free-flowing and non-dusting, and particularly they must not cake on storage even under fairly high temperatures such as about 60 C. (140 F.) or higher. If the colors cake in the drums or other containers in which they are shipped and stored, they will clog the eductor tube and render it inoperative.

Unfortunately, the otherwise desirable compounds used in this invention could not be used in this way. The commercially available powders are badly dusting, which not only contaminates other colors in the area but is a serious health hazard because, if inhaled, they can cause serious illness. The dusting problem alone can be solved by using various known dedusting agents, such as light mineral oils. Unfortunately, both colors used in the present invention, as previously available in finely divided powder form, cake seriously alone and even worse when treated with a dedusting agent. Thus, when heated to 65 C. for as little as two hours, a solid cake results, which is completely unusable in a dry dye eductor. Long storage at room temperature produces the same result.

According to the present invention, it is found that both the yellow dye and the orange dye of this invention can be converted to free-flowing, non-dusting platelets of suitable characteristics for use in a dry dye eductor. Moreover, these products are, for all practical purposes, noncaking. Thus, even when heated at 98 C. for three months, they still remain free-flowing and, of course, remain non-caking indefinitely at normal storage temperatures.

There is a definite limit on the dimensions of the platelets of the present invention. One dimension, which will be referred to as thickness, must be considerably smaller than their other dimensions. In order to dissolve at a sufliciently rapid rate to be practically useful, the platelets must not exceed about 1 mm. in thickness. Platelets with a thickness of 0.3 mm. or less are preferred.

The other dimensions are not as critical. In general, both length and breadth should be greater than 0.25 mm. so that the platelets are retained on a No. 60 sieve (U.S. Standard). The upper limit, should be sufficiently small that the platelets will pass through a No. 10 sieve (U.S. Standard). If the platelets are long but narrow and thin, the length may exceed slightly the opening of the No. 10 sieve. These dimensions are preferred for optimum solubility. Larger platelets can be used since the physical limit is placed by the smallest dimension in the eductor itself, which is commonly of the order of magnitude of one inch or somewhat less.

The behavior of the materials of this invention is surprising and an anomalous one. Closely related azo dyes in this form and size range cake badly. One such, e.g., the red dye obtained by diazotizing methyl substituted aminoazobenzenes and coupling to beta naphthol, is known as Oil Red N-1700. For brevity, this designation be used in the following examples. It is not known why the yellow and'orange dyes of the present invention exhibit such extraordinary resistance to caking in this form when their analogs do not.

The new form of these dyes which form our invention is prepared by a process which has critical limitations. The finely ground powder or dried unground press cake, in which forms the dyes are usually obtained, are melted in any convenient vessel. The oil orange melt is held at temperatures between 130 C. and 175 C. (preferably l60165 C.) while a drum is rotated in the melt. Simi larly the oil yellow melt is held between 112 and 165 C. (preferably 145 C.). The drum surface is held at a temperature of to C. for the yellow and 70 to C. for the orange, ranges that are very critical. The immersion of the drum in the melt must be held to a minimum. It should not be any greater than that which will produce a film of the dye no more than 1 mm. thick. This depth will vary depending on the viscosity of the melt. Scraper knives are positioned to remove the thin film of solidified dye from the drum as flakes.

Since these dyes are to be used in a dry dye eduction process, the rate of solubility in hydrocarbons such as gasoline is all important. This should not be confused with absolute solubility, which is an equilibrium phenomenon. No matter what the form of these dyes, they will eventually all dissolve in the hydrocarbon but the rate at which they do so controls their utility in the dry dye eduction 3 method. It is a general rule that substances dissolve more rapidly the more finely they are divided, i.e., the larger their surface area. It is therefore most unexpected to find that a process which greatly increases the particle 4 higher melting point of the material. The operation and tests are summarized as follows:

1 sq. ft. drum (6 inches 19 sq. ft. drum (2ft.

diameter) diameter by 3 ft.) size and decreases the surface area does not appreciably 5 reduce the fate of Solution Melt temperature 160165 o 165 C. The temperature of the drum is all 1mportant to the gmfi tr ag tempe rgture gg g ggsf o.

R rate of solution. If the drum surface 1s cooler than 70 i 304, nm 1%1509 r.p.m. Imm minimum the of 89111111110 fapldlyfans even though T11R13??? chips less than 0.3 mm less than 0.3 mm. proper partlcle size range is obtained. If the surface 1s hotter than 90 C. the melt does not solidify properly so that the knives can flake the film.

0 al 011 0 011 0 The 1nvent1on Wlll be described in greater detail 1n conon b ign e 6 D i' u ll 24" rii mii nection with the following specific examples in which 15 the parts are by weight unless otherwise specified. In Benzenetlnsolubles, 0 19 the examples, for the most part, the procedure h s been ESK; g gg'fi ig 'jjj y g done on two scales, one a laboratory scale with a small 625% g ge 0-0082 g./75 g-. 0. 0031 g./75 sdrum and another on a larger drum, which represents more C 2 Moderate Freeflowmg, nearly the conditions obtained in commercial plants. As 20 (121115 glf will be seen below, the quahty of the products did not 98 0.2m rln D 98 C. 3 mos do Do. vary with the size of the operation. Rate of 801,11 in stloddard Solv.: 97 3 100 96 07 mm n Example 1 33min 100%? The yellow dye (New Color Index No. 11020), the formula of which is in column 1, in the form of a dry Example 3 press cake, was melted and the melt heated to a tempera- An attempt to prepare platelets of on Red N 170O ture of 145 C. The melt Wasthen charged to a tray or using the procedure described in Example 1 did not give P of the apparatus for formmg Platelets Where It was a satisfactory product, when melt temperatures of 145 maintained at about the same temperature. A drum was to 155 Q, d temperatures f 34 C to 110 rotated with its lower portion immersed in the shallow pan C, and drum speeds 1 to 1 /2 r.p.m. were used. The recontaining the molten dye. Scraper knives were posisulting material was glassy and friable. tioned to remove the thin film of solidified dye from the The properties of Oil Red N-1700 obtained in this a 35 drum 1n the form of platelets. The platelets were then example are shownasfollows. fi g fi fig Sleve fi s f on Benzene insolubles, percent 0.57.

e. e a1 s o e opera 1011 are as ws. Caking test 65 C. 2 hrs Hard caking. lsq.ft.drum (6 inches 19 sq.it.drum 2a. 40 2 hrs D0.

diameter) diameter drum by 98 C 2 h C k lid 3 feet long) Example 4 ggg' ggfggg fig: Samples of Oil Orange prepared by the method of grum temteratllrenn 25 Example 2, using difierent drum temperatures are tested :11 minimum ,fi QE E by measuring how fast 0.1 g. dissolves in 100 cc. of a Thickness of platelets less than 0.3 mm. less than 0.3 mm. mixed hydrocarbon solvent. The results are as fOllOWS:

Two samples of the products were tested with a control, sample Flake Samples namely, ordinary powdered dye. Comparison for ben- Powder zene insoluble material, dusting, caking and rate of solul 2 3 4 5 tion in the standard Stoddard Solvent was made. The Drum Temperature (0 o 90 90 90 40 results were as follows: Par Size (Thicknes'si;

mm. 2;e% 0.22 0.21 0.29 0.71 0.459 55 held Original Oil 011 Yellow 6" Oil Yellow 24" gig Yellow Powder Drum Drum Rate of Solution: 7 Percent dissolved after Benzene Insolubles, 0.17 0.2a 0.17. -2 5% percent. .4 Dusting. Dusty No duet No dust. 0 ASTM dust test 0.021 g./75 g.-- 0.0017 g./75g 0.003s g./75 g. Oaking Test at:

65 (3., 2 hrs Moierate Free fl0wing Free flowing. 2 hrs gi gg do Similarly, the 011 Yellow of Example 1 is tested with 93 0., 2hrs l-- do Do. the following results: 98 0., 3 in Do. Raite gfssolln in Stod- 65 ar 9 v.: Flake Samples 15mm 957 97.57 99 7. e 30 min 97.4% 98.771, 100%. Sample ggg g g Example 2 70 glgmlignlempi, 0 .I 76 65 The orange dye (New Color Index No. 12055), the essmm g M87 0314 formula of which appears in column 1, was prepared in 31 the form of platelets by following the procedure of Exi g l f 9M 100 ample 1 and tested against the ordinary dye powder. 30 min 97.4-- Slightlyhigher temperatures were used because of the 75 1. In the process of preparing an oil soluble, dustless, non-caking form of the dye of the formula which comprises rotating a drum immersed in a melt of said dye and fracturing into flakes the thin film of solid dye so formed, the improvement of keeping the said melt at a temperature of ISO-175 C., keeping the drum surface at a temperature of 70-90 C. and having the said drum in contact with said melt to such a depth that the film of melt picked up is no more than 1 mm. in thickness.

References Cited in the file of this patent UNITED STATES PATENTS 2,007,386 Stanley et a1. July 9, 1935 2,263,616 Dahlen et a1 Nov. 25, 1941 2,492,163 Locke Dec. 27, 1949 2,773,056 Helfaer Dec. 4, 1956 OTHER REFERENCES Weissberger: Technique of Organic Chemistry, vol. III, 1950, pages 375, 392, 393, 43s. (Copy in Lib.) 

2. IN THE PROCESS OF PREPARING AN OIL SOLUBLE, DUSTLESS, NON-CAKING FORM OF THE DYE OF THE FORMULA 